1. Field of the Invention
The present invention relates to a device for optically rotating an image ninety degrees.
2. Description of the Prior Art
There are numerous different situations in which the ability to optically rotate an image by ninety degrees would be very useful. For example, the titles and authors of books are normally printed on the binding of books, and books are normally positioned upright on shelves of both public and private libraries. When stacked in this manner books are oriented in a vertical disposition, packed laterally together, so that a selected book may be withdrawn from between adjacent books with ease.
While some books are thick enough to allow the names of their titles and authors to be printed horizontally across the backs of the bindings when the books stand upright on library shelves, many books, indeed the great majority of books, are simply too thin to allow useful information to be printed on their bindings in this manner. Accordingly, it has been a frequent practice among book publishers to print names of authors and the titles of books lengthwise along the bindings of many books.
While information printed on book bindings in this manner can be read in the normal fashion with a lateral eye scan when the book is laid flat on a surface, the titles and authors become more difficult to read when the books are stacked on library shelves. The lettering on the book spines, instead of progressing horizontally from left to right so as to be easily read by the human eye, is tipped ninety degrees and progresses from either top to bottom or bottom to top. An individual seeking to read information from the spine of a book stacked in a library is therefore forced to tilt his or her head sideways to an extreme angle in order to be able to absorb the information printed on the book spine. Maintaining one's head in such a position to read information in such an awkward manner becomes quite tedious and uncomfortable.